Yemen officials say rebels shell civilian area north of port city of Aden, killing at least 45

Fighters against Shiite rebels known as Houthis gather in front of the airport in the port city of Aden, Yemen, Thursday, July 16, 2015. Saudi-backed Yemeni troops and fighters have driven Shiite rebels out of two major neighborhoods in the southern port city of Aden, Thursday, prompting street celebrations by residents after weeks of fierce fighting. (AP Photo/Abo Muhammed) (The Associated Press)

Fighters against Shiite rebels known as Houthis gather at the frontline of fighting against Houthis fighters in the port city of Aden, Yemen, Thursday, July 16, 2015. Saudi-backed Yemeni troops and fighters have driven Shiite rebels out of two major neighborhoods in the southern port city of Aden, Thursday, prompting street celebrations by residents after weeks of fierce fighting. (AP Photo/Abo Muhammed) (The Associated Press)

SANAA, Yemen – Medical officials say Shiite rebels and their allies randomly have bombed an area north of the southern city of Aden, killing at least 45 people.

The rebels are fighting to thwart an offensive by Saudi-backed troops and local fighters.

On Sunday, the officials said hundreds of residents fled Dar Saad, north of Aden, amid intense shelling from the rebels. They said at least 45 people, believed to be civilians, were killed. The officials spoke on condition of anonymity as they weren't authorized to brief journalists.

The Saudi-backed fighters, backed by Saudi-led coalition airstrikes, pushed the rebels out of Aden's airport and two major neighborhoods last week. The rebels vowed to retaliate.

Aden has been the scene of some of the war's most intense ground fighting since March.